In 1666, English scientist Sir Isaac Newton discovered that when pure white light is passed through a prism, it separates into all of the visible colors. Newton also found that each color is comprised of a single wavelength and cannot be separated any further into other colors.

Further experiments demonstrated that light could be combined to form other colors. For example, red light mixed with yellow light creates an orange color. A color resulting from a mix of two other colors is known as a metamer. Some colors, such as yellow and purple, cancel each other out when mixed and result in a white light. These competing colors are known as complements.

Colors in the red area of the color spectrum are known as warm colors and include red, orange, and yellow. These warm colors evoke emotions ranging from feelings of warmth and comfort to feelings of anger and hostility.

Colors on the blue side of the spectrum are known as cool colors and include blue, purple, and green. These colors are often described as calm, but can also call to mind feelings of sadness or indifference.

Color Psychology as Therapy

Several ancient cultures, including the Egyptians and Chinese, practiced chromotherapy, or using colors to heal. Chromotherapy is sometimes referred to as light therapy or colourology and is still used today as a holistic or alternative treatment.

In this treatment:

Red was used to stimulate the body and mind and to increase circulation.

Yellow was thought to stimulate the nerves and purify the body.

Orange was used to heal the lungs and to increase energy levels.

Blue was believed to soothe illnesses and treat pain.

Indigo shades were thought to alleviate skin problems.

Most psychologists view color therapy with skepticism and point out that the supposed effects of color have been exaggerated. Colors also have have different meanings in different cultures. Research has demonstrated in many cases that the mood-altering effects of color may only be temporary. A blue room may initially cause feelings of calm, but the effect will be dissipate after a short period of time.

Like death and taxes, there is no escaping color. It is ubiquitous. Yet what does it all mean? Why are people more relaxed in green rooms? Why do weightlifters do their best in blue gyms?

Colors often have different meanings in various cultures. And even in Western societies, the meanings of various colors have changed over the years. But today in the U.S., researchers have generally found the following to be accurate.

Black is often used as a symbol of menace or evil, but it is also popular as an indicator of power. It is used to represent treacherous characters such as Dracula and is often associated with witchcraft.

Black is associated with death and mourning in many cultures. It is also associated with unhappiness, sexuality, formality, and sophistication.

White is also described as cold, bland, and sterile. Rooms painted completely white can seem spacious, but empty and unfriendly. Hospitals and hospital workers use white to create a sense of sterility.

Red is also considered an intense, or even angry, color that creates feelings of excitement or intensity.

Consider how red is used in language: redneck, red-hot, red-handed, paint the town red, seeing red.

The Color Psychology of Blue

Blue is described as a favorite color by many people and is the color most preferred by men. Women tend to buy blue clothing for men because they believe men prefer it.

Blue calls to mind feelings of calmness or serenity. It is often described as peaceful, tranquil, secure, and orderly.

Blue can also create feelings of sadness or aloofness.

Blue is often used to decorate offices because research has shown that people are more productive in blue rooms.

Blue is one of the most popular colors, but it is one of the least appetizing. Some weight loss plans even recommend eating your food off of a blue plate. Blue rarely occurs naturally in food aside from blueberries and some plums. Also, humans are geared to avoid foods that are poisonous and blue coloring in food is often a sign of spoilage or poison.

Blue can also lower the pulse rate and body temperature.

Consider how blue is used in language: blue moon, blue Monday, blue blood, the blues, and blue ribbon.

Researchers have also found that green can improve reading ability. Some students may find that laying a transparent sheet of green paper over reading material increases reading speed and comprehension.

Green has long been a symbol of fertility and was once the preferred color choice for wedding gowns in the 15th-century. Even today, green M & M's (an American chocolate candy) are said to send a sexual message.

Green is often used in decorating for its calming effect. For example, guests waiting to appear on television programs often wait in a “green room” to relax.

Green is thought to relieve stress and help heal. Those who have a green work environment experience fewer stomachaches.

Consider how green is used in language: green thumb, green with envy, greenhorn.

Yellow is also the most fatiguing to the eye due to the high amount of light that is reflected. Using yellow as a background on paper or computer monitors can lead to eyestrain or vision loss in extreme cases.

Yellow can also create feelings of frustration and anger. While it is considered a cheerful color, people are more likely to lose their tempers in yellow rooms and babies tend to cry more in yellow rooms.

Yellow can also increase the metabolism.

Since yellow is the most visible color, it is also the most attention-getting color. Yellow can be used in small amount to draw notice, such as on traffic sign or advertisements.

Purple does not often occur in nature, it can sometimes appear exotic or artificial.

The Color Psychology of Brown

Brown is a natural color that evokes a sense of strength and reliability.

Brown can also create feelings of sadness and isolation.

Brown brings to mind feeling of warmth, comfort, and security. It is often described as natural, down-to-earth, and conventional, but brown can also be sophisticated.

The Color Psychology of Orange

Orange is a combination of yellow and red and is considered an energetic color.

Orange calls to mind feelings of excitement, enthusiasm, and warmth.

Orange is often used to draw attention, such as in traffic signs and advertising.

Colors of the Flag

In the U.S. flag, white stands for purity and innocence. Red represents valor and hardiness, while blue signifies justice, perseverance, and vigilance. The stars represent the heavens and all the good that people strive for, while the stripes emulate the sun's rays.

Food for Thought

While blue is one of the most popular colors it is one of the least appetizing. Blue food is rare in nature. Food researchers say that when humans searched for food, they learned to avoid toxic or spoiled objects, which were often blue, black, or purple. When food dyed blue is served to study subjects, they lose appetite.

Green, brown, and red are the most popular food colors. Red is often used in restaurant decorating schemes because it is an appetite stimulant.